19 Breast Cancer

440 Breast Cancer

C: Indication of new entrance and exit points, further away from the boost CTV, to avoid skin teleangiectases. D: Occurrence of severe teleangiectasic “stars” at skin entrance or exit points if rules for implantation are not followed (see text) Ultrasonography, CT (Fig 18.4) and MRI may also be used for locating the tumour area more precisely and may possibly help to reduce side effects and breast recurrences by eliminating geographic misses (33,43). By means of CT and marker clips it has been possible to further reduce the volume of the boost which still improving local control rates (20).

Fig 18.4 : Using CT and clip localisation for localising the boost PTV (with courtesy of J. Hammer) In some cases, after localisation of the PTV and inclination of the needle implant, the presumed entrance or exit points may be too close to the target area. Then, it may be advised to change the inclination of the equator, so that target area and the skin points got sufficiently separated (Fig 18.3B,C) and the occurrence of star-like tele-angiectasia at exit and entrance points (Fig 18.3D) is avoided.

7.2 Technique of implantation Breast implants can easily be carried out under local anaesthesia and pre-medication with f.i. 2.5 to 5mg midazolam (Dormicum ® ) given 15-30 minutes before the implantation. The patient is installed in supine position, with the homolateral arm in 90° abduction. 7.2.1 Design of the implant geometry: Once the tumour centre is localised, and the three dimensions of the clinical target volume and the PTV (length, width, and thickness) are defined, the implant geometry is designed according to the rules of the Paris System (see physics chapter):